/*
package NiuKe;

import java.util.List;
import java.util.Scanner;
import java.util.Stack;

*/
/**
 * @Description:
 * @Author: Hanzao
 * @Date: 2022/06/12/21:25
 *//*

public class HJ9 {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);
        int num = scanner.nextInt();
        Stack stack = new Stack();
        Stack stack2 = new Stack();
        int tmp;
        while(num!=0){
            tmp = num%10;
            if(!stack.contains(tmp)){
                stack.push(tmp);
            }
            num = num/10;
        }

        while(!stack.isEmpty()){
            stack2.push(stack.peek());
            stack.pop();
        }
        while(!stack2.isEmpty()){
            System.out.print(stack2.peek());
            stack2.pop();
        }
    }
}
*/
